The present invention relates to the field of image recording and reproduction and, more particularly, to a hybrid type of image recording and reproduction system which combines aspects of both photography and electronic imaging.
Electronic still image camera systems are known in the prior art. Typically, the camera utilizes a solid state image sensor, such as a CCD or the like, which employs a matrix array of photosensitive elements for converting an optical image of the scene focused thereon into electronic image signals which define the scene on a pixel by pixel basis. The image signals generally are digitized and then recorded on an appropriate storage medium, such as a magnetic tape or disk. The recorded image may be displayed electronically by feeding the image signals to a display device, such as a CRT, or a "hard copy" print may be obtained by sending the image signals to a printer.
For a representative example of an electronic still image camera which also includes a built-in display screen and printer, reference may be had to U.S. Pat. No. 4,262,301 issued to Irving Erlichman on Apr. 14, 1981.
There are many advantages to be derived from electronic imaging. For example, once the image is converted into digital signal form, the image may be improved or otherwise modified beneficially utilizing a variety of image enhancement algorithms and signal processing techniques. Parameters that may be improved in this way include contrast, image sharpness, color saturation, and balancing of color to better match the spectral characteristics of an intended display or print medium. Also, the digitized image signals may be stored in a data base to facilitate retrieval; several copies of the image may be made to apply different enhancement techniques thereto; and the image signals may be transmitted quickly to remote locations utilizing various types of data communication systems.
Enthusiastic forecasts that a compact, hand held, electronic still image camera would reach the market within a year or two after several product announcements now are being tempered and downplayed because those actively working in this field realize that significant advances in the state of the art relating to solid state image sensors will be necessary before such cameras achieve acceptable image quality and can be manufactured at reasonable cost.
It is envisioned that utilization of a solid state image sensor will be the key to compactness and low cost. However, commercially available solid state image sensors, while small, currently have severe resolution limitations which impair image quality, and are very expensive. At this time, these sensors generally are capable of only dividing an image focus thereon into a matrix array on the order of 512 by 512 pixels. Thus, the resolution of these sensors is orders of magnitude lower than that of photographic film and, not withstanding improvements provided by enhancement techniques, images reproduced from electronic image signals generated by such cameras are relatively coarse in terms of photographic quality.
To electroncially record an image in color, it is necessary to generate three primary color signals, typically red, green, and blue. If the resolving power of commericially available sensors is to be maintained, three sensors must be employed, one for each of the three primary colors, which substantially increases cost. If, in the interest of reducing cost, a single sensor is used in combination with a three color filter array in front of the photosensitive elements, resolution is effectively lowered by one third because only one third of the photosensitive elements "look at" each color.
Because low cost, high resolution, solid state image sensors are not available yet, there is a current need for an alternative approach which will provide a system that is capable of producing high quality images without requiring an image sensor that is beyond the current state of the art.
Therefore, it an object of the present invention to provide a system that may be assembled from existing components and materials and yet is capable of recording and reproducing quality images in color while exploiting the advantages of electronic imaging.
It is another object to provide such a system which records the luminance component of a color image in high resolution and its chromanance component and low resolution, yet is capable of reproducing a high quality color image.
Another object is to provide for such a system which is hybrid in nature in that it combines aspects of both photography and electronic imaging.
Still another object is to provide such a system that does not require a high resolution electronic image sensor to record the luminance component of the image.
Other objects will, in part, be obvious and will, in part, appear hereinafter.